diff --git a/osu.Game.Tests/Visual/Online/TestSceneBeatmapRulesetSelector.cs b/osu.Game.Tests/Visual/Online/TestSceneBeatmapRulesetSelector.cs
index 36c3576da6..599eee7d0c 100644
--- a/osu.Game.Tests/Visual/Online/TestSceneBeatmapRulesetSelector.cs
+++ b/osu.Game.Tests/Visual/Online/TestSceneBeatmapRulesetSelector.cs
@@ -44,7 +44,7 @@ namespace osu.Game.Tests.Visual.Online
 
                 selector.BeatmapSet = new APIBeatmapSet
                 {
-                    Beatmaps = selector.BeatmapSet.Beatmaps
+                    Beatmaps = selector.BeatmapSet!.Beatmaps
                                        .Where(b => b.Ruleset.OnlineID != ruleset)
                                        .Concat(Enumerable.Range(0, count).Select(_ => new APIBeatmap { RulesetID = ruleset }))
                                        .ToArray(),
diff --git a/osu.Game/Online/Rooms/JoinRoomRequest.cs b/osu.Game/Online/Rooms/JoinRoomRequest.cs
index a1d6ed1e82..8645f2a2c0 100644
--- a/osu.Game/Online/Rooms/JoinRoomRequest.cs
+++ b/osu.Game/Online/Rooms/JoinRoomRequest.cs
@@ -10,9 +10,9 @@ namespace osu.Game.Online.Rooms
     public class JoinRoomRequest : APIRequest
     {
         public readonly Room Room;
-        public readonly string Password;
+        public readonly string? Password;
 
-        public JoinRoomRequest(Room room, string password)
+        public JoinRoomRequest(Room room, string? password)
         {
             Room = room;
             Password = password;
diff --git a/osu.Game/Rulesets/Difficulty/PerformanceBreakdownCalculator.cs b/osu.Game/Rulesets/Difficulty/PerformanceBreakdownCalculator.cs
index 64a04f896f..8b59500f43 100644
--- a/osu.Game/Rulesets/Difficulty/PerformanceBreakdownCalculator.cs
+++ b/osu.Game/Rulesets/Difficulty/PerformanceBreakdownCalculator.cs
@@ -8,6 +8,7 @@ using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using JetBrains.Annotations;
+using osu.Framework.Extensions.ObjectExtensions;
 using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Mods;
 using osu.Game.Rulesets.Objects;
@@ -88,7 +89,7 @@ namespace osu.Game.Rulesets.Difficulty
                 ).ConfigureAwait(false);
 
                 // ScorePerformanceCache is not used to avoid caching multiple copies of essentially identical perfect performance attributes
-                return difficulty == null ? null : ruleset.CreatePerformanceCalculator()?.Calculate(perfectPlay, difficulty.Value.Attributes);
+                return difficulty == null ? null : ruleset.CreatePerformanceCalculator()?.Calculate(perfectPlay, difficulty.Value.Attributes.AsNonNull());
             }, cancellationToken);
         }
 
diff --git a/osu.Game/Screens/OnlinePlay/Match/RoomBackgroundScreen.cs b/osu.Game/Screens/OnlinePlay/Match/RoomBackgroundScreen.cs
index 982275f96a..53a52a8cb8 100644
--- a/osu.Game/Screens/OnlinePlay/Match/RoomBackgroundScreen.cs
+++ b/osu.Game/Screens/OnlinePlay/Match/RoomBackgroundScreen.cs
@@ -9,9 +9,9 @@ namespace osu.Game.Screens.OnlinePlay.Match
 {
     public partial class RoomBackgroundScreen : OnlinePlayBackgroundScreen
     {
-        public readonly Bindable<PlaylistItem> SelectedItem = new Bindable<PlaylistItem>();
+        public readonly Bindable<PlaylistItem?> SelectedItem = new Bindable<PlaylistItem?>();
 
-        public RoomBackgroundScreen(PlaylistItem initialPlaylistItem)
+        public RoomBackgroundScreen(PlaylistItem? initialPlaylistItem)
         {
             PlaylistItem = initialPlaylistItem;
             SelectedItem.BindValueChanged(item => PlaylistItem = item.NewValue);